QRCode Generator

Generate customizable QR codes from text or URLs. Supports multiple formats (SVG/PNG/JPG) with styling options.

Agent Instructions

After generating QR codes, you MUST:

1. Display the generated file using appropriate markdown syntax:
   • For images (PNG/JPG): ![QR Code](sandbox:/path/to/file.png)
   • For SVG: Display as image or provide download link
2. Confirm the file path and format to the user
3. Offer to regenerate with different styling if needed

Quick Start

# Basic usage (auto-generated filename)
node {baseDir}/scripts/generate.mjs "Hello World"

# Custom styled QR code
node {baseDir}/scripts/generate.mjs "https://example.com" -o myqr.svg --dot circle --eye rounded --color "#2563eb"

# High-resolution transparent PNG
node {baseDir}/scripts/generate.mjs "Contact Info" --format png --size 2048 --transparent

# Print-quality JPEG
node {baseDir}/scripts/generate.mjs "https://example.com" --format jpg -o qr.jpg --size 2048 --quality 95

Options

Output

• -o, --out <filename> - Output filename (workspace root only). Default: qrcode_<text>_<timestamp>.<ext>
• --format <svg|png|jpg> - Output format (default: svg)

Dimensions

• --size <px> - Base pixel size (default: 1024, max: 10000)
• --scale <n> - Resolution multiplier (default: 1, max: 10)
• --margin <modules> - Quiet zone size (default: 4, max: 100)

Styling

• --dot <square|circle> - Data module shape (default: square)
• --eye <square|circle|rounded> - Finder pattern style (default: square)
• --color <#RRGGBB> - Foreground color (default: #000000)
• --background <#RRGGBB> - Background color (default: #ffffff)
• --transparent - Transparent background (PNG only, ignored for SVG/JPG)

Quality

• --ec <L|M|Q|H> - Error correction: Low/Medium/Quality/High (default: M)
  • L (~7%): Clean environments, maximum data capacity
  • M (~15%): General use, balanced capacity/reliability
  • Q (~25%): Styled QR codes, moderate damage tolerance
  • H (~30%): Logo embedding, heavy styling, outdoor use
• --quality <1-100> - JPEG compression quality (default: 80)

File Handling

Security-enforced workspace root output:

• All files saved to workspace root directory only
• Path components stripped: -o ../path/file.svg → workspace/file.svg
• Auto-generated filenames include sanitized text and timestamp
• Maximum text length: 4096 characters

Installation

cd {baseDir}
npm install

Dependencies: qrcode (matrix generation), sharp (image conversion)

Platform notes: macOS requires Xcode Command Line Tools. See sharp docs for other platforms.

Examples

WiFi QR Code

node {baseDir}/scripts/generate.mjs "WIFI:S:MyNetwork;T:WPA;P:password123;;" --format png -o wifi.png --size 1024

Styled Business Card

node {baseDir}/scripts/generate.mjs "BEGIN:VCARD
VERSION:3.0
FN:John Doe
TEL:+1234567890
EMAIL:john@example.com
END:VCARD" --dot circle --eye rounded --color "#1e40af" --background "#eff6ff" -o contact.svg

High-Resolution Print

node {baseDir}/scripts/generate.mjs "https://example.com" --format jpg --size 4096 --quality 95 --ec H -o print.jpg

Transparent Logo Overlay

node {baseDir}/scripts/generate.mjs "https://example.com" --format png --size 2048 --transparent --margin 2 -o overlay.png

Logo Embedding (Requires High Error Correction)

# Use --ec H when QR code will have logo overlay (covers ~20-30% of center)
node {baseDir}/scripts/generate.mjs "https://example.com" --format png --size 2048 --ec H -o logo-base.png

Security Features

• ✅ Path traversal protection - All outputs forced to workspace root
• ✅ Symlink attack prevention - Atomic writes with verification
• ✅ Input validation - Length limits (4096 chars), character whitelisting
• ✅ Filename sanitization - Dangerous characters stripped from filenames
• ✅ Resource limits - Max size/scale to prevent DoS attacks

Troubleshooting

Issue	Solution
npm install fails	Install build tools:xcode-select --install (macOS) or see sharp install guide
QR code won't scan	Increase --size, use higher error correction (--ec H), or simplify styling
Colors not working	Use hex format #RRGGBB (e.g., #FF5733), not RGB or color names
File too large	Reduce --size, --scale, or increase --quality for JPG
Permission denied	Check workspace directory write permissions

Error Correction Levels Explained

Error correction allows QR codes to remain scannable even when partially damaged or obscured:

Level	Recovery Capacity	Data Capacity	Use Case
L	~7% damage	Maximum	Clean environments, screen display, maximum data
M	~15% damage	High	General use (default), standard printing
Q	~25% damage	Medium	Styled designs (circles/rounded), possible minor damage
H	~30% damage	Minimum	Logo embedding, outdoor use, heavy styling, print-on-print

Key principle: Higher error correction = more damage tolerance but less data capacity.

When to use H level:

• Embedding logos (covers 20-30% of center)
• Circular dots or rounded eyes
• Outdoor/weathered environments
• Low-quality printing
• Stickers that may peel/scratch

Format Comparison

Format	Transparency	Quality	File Size	Use Case
SVG	✅	Infinite	Smallest	Web, scalable graphics
PNG	✅	Lossless	Medium	Digital displays, overlays
JPG	❌	Lossy	Smallest*	Print, photos, email

*With compression

Tips

• Scanning distance: Use --size 1024 for mobile (1-2m), --size 2048+ for print/posters
• Styling vs. reliability: Higher --ec levels compensate for --dot circle or --eye rounded
• Transparent backgrounds: Use PNG format with --transparent; JPG always uses white/specified background
• File size optimization: SVG for web, JPG with --quality 80-85 for print
• Data capacity: L/M/Q/H levels affect max alphanumeric capacity: ~4296/3391/2420/1852 chars (Version 40)
• Logo placement: Use --ec H and leave center area clear (approximately 30% of QR code)

Common Use Cases

Scenario	Recommended Settings
Website URL	--format png --size 1024 --ec M
WiFi credentials	--format png --size 1024 --ec M
Business card (vCard)	--format svg --dot circle --eye rounded --ec Q
Print poster	--format jpg --size 4096 --quality 95 --ec H
Logo overlay base	--format png --size 2048 --ec H --transparent
Email signature	--format png --size 512 --ec M
Product packaging	--format svg --ec H (scalable for any print size)
Outdoor signage	--format jpg --size 2048+ --ec H --quality 90
Social media profile	--format png --size 1024 --transparent --dot circle --ec Q
Payment QR (high density)	--format png --size 2048 --ec L --margin 2 (maximize capacity)